The Tellus Border project was a cross-border geo-environmental mapping project of Northern Ireland and the northern counties of the Republic of Ireland. The project was led by the Geological Survey of Northern Ireland in partnership with the Geological Survey of Ireland. Funding of £4,555,396 was provided by the INTERREG IVA programme. The project was a significant undertaking:

First, it involved major data collection tasks covering more than 12,000km², with soil, water, sediment and vegetation samples from 3,500 sites and geophysical data from a low-flying plane which flew over 57,600km.

Second, the data collection affected a wide range of stakeholders, in particular landowners and​ farmers, and there was a potential for adverse publicity about the survey.

Thirdly, the project collated, processed and analysed an immense volume of data. This included over 50 million geophysical measurements and over 750,000 geochemical analyses for soil, stream water and stream sediments.

Finally, the project engaged with a wide range of stakeholders, generated interest in the data and made the data available in a form that could be accessed.